Telephones have become an indispensable tool of communication between people. With the fast development of mobile communications technology, people nowadays can utilize a handset to communicate with others at any time, and meanwhile, Internet Protocol-based (IP-based) telephony, known as Voice over IP (VoIP), is starting to gain ground in the field of mobile communications. However, traditional mobile phones and IP-based mobile phones have a common problem that needs to be solved, that is, how disturbances caused by the ringing sounds of incoming calls can be avoided when a mobile phone user is in an environment (such as a hospital, a conference room, or a theater) where disturbances are considered annoying.
Thus, the European patent publication no. EP1035748 A1, entitled “Switching a mobile terminal to a silent ring mode,” proposes a method for switching a mobile terminal to a silent ring mode by means of periodically broadcasting a good manner signal (i.e., a request for switching the ring mode) to a mobile terminal in a predetermined area to switch the ring mode of the mobile terminal.
However, the aforesaid patent has the following drawbacks. First, supposing the mobile terminal has received a call just prior to receiving the good manner signal in the predetermined area, the mobile terminal will still use its original ring mode. Second, settings of the mobile terminal have to be changed in order to achieve the intended objective of the aforesaid patent.
Furthermore, referring to FIG. 1, a conventional way of achieving the objective of preventing disturbance caused to a predetermined area 3 (i.e., the environment to be protected from disturbance) by a mobile device 21 that is located in the predetermined area 3 is described as follows. First, a caller 10 outside the predetermined area 3 calls the mobile device 21 of a callee 20 using an originating mobile device 11. The telephone signal is transmitted in a network telephony-adopted form to a hub 25. Then, the hub 25 broadcasts the telephone signal to a plurality of access points (AP) 22, 23, 24 within the predetermined area 3. Next, as indicated by a signal direction 29, the mobile device 21 can receive the telephone signal through the access point 22. However, in order to avoid disturbance caused to the predetermined area 3 by a ringing sound that is generated when the mobile device 21 receives the telephone signal, the callee 20 must manually change the ring mode of the mobile device 21 to a silent or vibration mode, which is inconvenient to the callee 20 and therefore needs to be efficiently resolved.